Leo daft



(No Model.)

L. DAFT. ELECTRIC MOTOR. No. 336,629. Patented Peb. 23, 1886.

llNrTeD STATES PATENT Gerlos.

LEO DAFT, OE GREENVILLE, NEWT JERSEY.

ELECTREC MOTOR.

PECIFICATION forming part of Letters Patent No. 336,629, dated February23, 1886.

Application led May 26, 1F85.

To all whom it' may concern.-

Be it known that I, LEO DAFT, a citizen of the United States, residingat Greenville. in the county ot' Hudson and State of New LTersey, haveinvented certain new and uset'ul Improvements in Electric Motors, ofwhich the following is a specification.

Myinvention relates to electric motors, and more particularly to themeans for reversing the same; and it has for its object to improve theconstruction of the reversing mechanism or brush-carriers, so that theymay be readily and easily operated, and so that the brushes shall bearupon the commntator when in use in such a manner as to secure thehighest ef ciency and the least wear at the points of contact, and sothat they may be readily thrown out of contact with the commutator whendesired.

To these ends my invention consists in a mechanism constructedsubstantially as hereinafter pointed out.

In the accompanying drawing is shown a side view oi' one well-known typeof motor with my improvements attached.

It is w ell'lr nown that in the use of electric motorssuch, for instance, as are employed on electric locomotives-it is necessary tofrequently change or reverse the direction of rotation ot' the armature,and one convenient way of so doing is to change the relative positionsofthe brushes on the com mutator, so as to cause the current to passthrough the coils of the armatures in diii'erent directions. It oftenhappens, also, that it is desired to withdraw the current entirely fromthe commutator, as when the locomotive is running by its momentum alone.

It is well recognized that the most efficient way of placing the brushesis to lhave them inclined to the face of the commutator in the directionot' its rotation, and not only does the current pass with lessresistance, but the wear upon the brushes is much less than when theyare placed. in a radial line to the axis of the commutator or at aninclination opposed to the direction of rotation of the armature.

In carrying out these improvements I construct the brushes and make thecircuit-counections as follows; In the drawing, the eldmagnets arerepresented by F, the armature by M, with the commutator O xed upon theSerial No. 166,718. (No model.)

armature-shaft P, supported in the frame Q. Alsolooselysupported uponthearmature-shaft is the rocking lever B. Secured to the ends of thislever, by pins or bolts passing through insulating-bearings I). are thegnide-levers A, the outer ends ot which are provided with guides a,ruiming in slots c in the extension ot' the frame Q. rIhe lnush-carriersD are rigidly secured to the inner ends ofthe guidelevers A, andproperly insulated therefrom, and each brush-carrieris provided withapair of brushes. as l 3 and 2 4, placed at an angle to each other, asshown. Some suitable operating means is connected tothe rocking` lever,as the rod E, and attached handle, E, moving over t-he sector E2. Thecircuit-connections are made so that one brush on each side of theconnnutator, as l and 2, have a common terminal, which, for example, inthe drawing is shown to be connected to the inner end ofthe field-magnetcoil, and similarly the brushes 3 and 4. are connected to theline-circuit.

From this construction it will be seen that when the reversinglever isthrown over, as shown in the drawing, the brushes l and 4 only will bearupon the commutator at diametrically-opposite points, and the directionof rotation of the armature will be that indicated by the arrow, and itwill be evident when the rocking lever is thrown over to the otherextreme of the sector that the brushes 2' and 3 will engage with thecommutator at diametrically-opposite points, and the direction ofrotation of the armature will be reversed by the evident reversal of therelations be tween the currents passing through the armature and theheld-magnets. A

It will be observed that whatever the direc` tion ot' the armature thebrushes will bear upon the commutator in such a position as to producethe best results electrically and produce the least wear. Then it isdesired to allow the motor to run by its momentum or otherwise,independent of the current,the reversing-lever will occupy anintermediate position on the sector, and all the brushes will be freefrom the commutator.

It is evident that the construction and ar rangement of the mechanicaldevices may be varied from that shown to meet the exigen` cies of theparticular construction of the various motors without departing from thespirit of my invention, and that parts of the mechanismdescribed may beused alone or with other equivalent devices.

l. In an electric motor, a rocking lever having a pair of brushes ateach end arranged With their inner ends projecting from each other, oneof the brushes of each pair having a common terminal, and mechanism,substantially as described, whereby each diametrically-opposite pair maybe brought into contact with the commutator at an angle to the directionof rotation of the commutator, as set forth.

2. The combination, in an electric motor,of a rocking lever, guideleverssecured to the ends of the lever and Working in guide-slots, a pair ofbrushes secured to the rods, and operating devices, substantially asdescribed, whereby either pair of the diametrically-opposite brushes maybe brought into contact ,with the commutator, as set forth.

3. The combination, in an electric motor,of an armature-shaft andcommutator securedthereto, a rocking lever on said shaft, guide1everssecured to the ends of said lever and Workingin slots in the frame ofthe machine, a pair of brushes secured to the guide-levers, havingoutwardly-projecting rods, and one brush of each pair havinga commonterminal, and a 3o hand-lever forn changing the position of the brushes,so that they will bear upon the commutator at an angle to the directionof rota tion of the same, or so that none of the brushes will touch it,substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

LEO DAFT.

Witnesses:

J No. N. BRUNs, F. H. REED.

